The present invention relates to magnetic disc storage systems for magnetically storing information. More specifically, the present invention relates to a technique for reducing wear in a magnetic disc storage system which uses a proximity recording head.
Magnetic disc drives are used to store magnetically encoded information. As the magnetic disc spins, a transducing head "flies" over and contacts the surface of the disc. The transducing head is used to sense magnetic fields from the disc surface during readback of information, and generate magnetic fields which are impressed onto the surface of the disc during writing of information. As the disc spins, the transducing head is supported by an "air bearing" which is formed between the disc surface and a slider body of the transducer head assembly. The slider body has aerodynamic properties which provide a lifting force.
It is known that improved magnetic interaction between the disc surface and the transducing head can be achieved by reducing the spacing between the head and the disc surface. One technique for reducing fly height is to employ a "proximity recording head." This provides a limited, intermittent contact between the recording head and the surface of the disc. There are two general types of proximity recording. These are glide contact (GC) recording and ultralow fly (ULF) recording. Glide contact assumes continuous contact between the slider and the disc. Ultralow fly recording assumes that there will be intermittent contact. One example of a proximity recording slider is described in U.S. Pat. No. 5,128,822 entitled "CONFIGURATION FOR NEGATIVE PRESSURE AIR BEARING SLIDERS," issued Jul. 7, 1992.
Proximity head recording provides the benefit of high areal density, which refers to the amount of information that can be stored per unit of disc area. Another means of providing high areal density is through magnetoresistive (MR) technology. MR technology currently suffers from the disadvantages of processing difficulties and poor manufacturing yields, which are reflected in higher prices. Proximity head recording provides high areal density at a substantially lower cost than its alternative, MR technology.
The continuous or intermittent contact between the head and the disc surface in proximity head recording, however, causes wear of the surfaces. This wear may result in release of particles which reduce the aerodynamic properties of the slider. Further, this can lead to debris collection on the slider surface, modulation of the readback signal and degradation of the lubrication at the interface.
One technique to reduce contact between the active, recording area of the disc surface and the slider as much as possible is to move the alternate slider to a resting position on the inner or outer tracks. Although this solution does not damage a single active track of the disc, the amount of wear on the slider and debris generation is not reduced.